You can find out what collations are supported on your current instance of MySQL. Here's output from my MySQL 5.7 instance:
mysql> select * from information_schema.collations where character_set_name='utf8mb4';
+------------------------+--------------------+-----+------------+-------------+---------+
| COLLATION_NAME | CHARACTER_SET_NAME | ID | IS_DEFAULT | IS_COMPILED | SORTLEN |
+------------------------+--------------------+-----+------------+-------------+---------+
| utf8mb4_general_ci | utf8mb4 | 45 | Yes | Yes | 1 |
| utf8mb4_bin | utf8mb4 | 46 | | Yes | 1 |
| utf8mb4_unicode_ci | utf8mb4 | 224 | | Yes | 8 |
| utf8mb4_unicode_520_ci | utf8mb4 | 246 | | Yes | 8 |
...
There are also a bunch of national collations.
There are new collations in MySQL 8.0 for the updated UCA 9.0.0 standard:
| utf8mb4_0900_ai_ci | utf8mb4 | 255 | Yes | Yes | 0 | NO PAD |
| utf8mb4_0900_as_ci | utf8mb4 | 305 | | Yes | 0 | NO PAD |
| utf8mb4_0900_bin | utf8mb4 | 309 | | Yes | 1 | NO PAD |
And more national collations.
There's really good docs on the new collations here: https://dev.mysql.com/doc/refman/8.0/en/charset-unicode-sets.html